White Nights is an international arts festival held during the arctic season when the sun is still visible at midnight. Part of the event is the Scarlet Sails, in which a ship with red sails sets off along the Neva River, accompanied by fireworks, entertainers, and an audience of millions. The tradition began after World War II, when students united to celebrate the end of the school year. The event soon became a demonstration of freedom from school and conformity against a backdrop of totalitarian communist rule.